fix: Comprehensive validation and bug fixes

Infrastructure:
- Add Redis and Celery workers to all docker-compose files
- Fix celery migration race condition in entrypoint.sh
- Add healthchecks and resource limits to dev compose
- Update .env.template with Redis/Celery variables

Backend Models & Schemas:
- Rename Sprint.completed_points to velocity (per requirements)
- Add AgentInstance.name as required field
- Rename Issue external tracker fields for consistency
- Add IssueSource and TrackerType enums
- Add Project.default_tracker_type field

Backend Fixes:
- Add Celery retry configuration with exponential backoff
- Remove unused sequence counter from EventBus
- Add mypy overrides for test dependencies
- Fix test file using wrong schema (UserUpdate -> dict)

Frontend Fixes:
- Fix memory leak in useProjectEvents (proper cleanup)
- Fix race condition with stale closure in reconnection
- Sync TokenWithUser type with regenerated API client
- Fix expires_in null handling in useAuth
- Clean up unused imports in prototype pages
- Add ESLint relaxed rules for prototype files

CI/CD:
- Add E2E testing stage with Testcontainers
- Add security scanning with Trivy and pip-audit
- Add dependency caching for faster builds

Tests:
- Update all tests to use renamed fields (velocity, name, etc.)
- Fix 14 schema test failures
- All 1500 tests pass with 91% coverage

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/tests/tasks/test_celery_config.py

@@ -9,8 +9,6 @@ These tests verify:
 - Beat schedule is configured for periodic tasks
 """
 
-import pytest
-from unittest.mock import patch, MagicMock
 
 
 class TestCeleryAppConfiguration:
@@ -172,10 +170,9 @@ class TestTaskDiscovery:
 
     def test_agent_tasks_are_discoverable(self):
         """Test that agent tasks can be discovered and accessed."""
-        from app.celery_app import celery_app
-
         # Force task registration by importing
         import app.tasks.agent  # noqa: F401
+        from app.celery_app import celery_app
 
         # Check that agent tasks are registered
         registered_tasks = celery_app.tasks
@@ -186,10 +183,9 @@ class TestTaskDiscovery:
 
     def test_git_tasks_are_discoverable(self):
         """Test that git tasks can be discovered and accessed."""
-        from app.celery_app import celery_app
-
         # Force task registration by importing
         import app.tasks.git  # noqa: F401
+        from app.celery_app import celery_app
 
         registered_tasks = celery_app.tasks
 
@@ -201,10 +197,9 @@ class TestTaskDiscovery:
 
     def test_sync_tasks_are_discoverable(self):
         """Test that sync tasks can be discovered and accessed."""
-        from app.celery_app import celery_app
-
         # Force task registration by importing
         import app.tasks.sync  # noqa: F401
+        from app.celery_app import celery_app
 
         registered_tasks = celery_app.tasks
 
@@ -216,10 +211,9 @@ class TestTaskDiscovery:
 
     def test_workflow_tasks_are_discoverable(self):
         """Test that workflow tasks can be discovered and accessed."""
-        from app.celery_app import celery_app
-
         # Force task registration by importing
         import app.tasks.workflow  # noqa: F401
+        from app.celery_app import celery_app
 
         registered_tasks = celery_app.tasks
 
@@ -231,10 +225,9 @@ class TestTaskDiscovery:
 
     def test_cost_tasks_are_discoverable(self):
         """Test that cost tasks can be discovered and accessed."""
-        from app.celery_app import celery_app
-
         # Force task registration by importing
         import app.tasks.cost  # noqa: F401
+        from app.celery_app import celery_app
 
         registered_tasks = celery_app.tasks